To Örebro University

Lithium demand is increasing due to its widespread use in rechargeable batteries, raising concerns about its release into aquatic environments. The bioavailability and toxicity of lithium under aquatic test conditions can be influenced by water chemistry and experimental conditions such as pH and exposure vessel material. This study investigated effects of plate material and pH on lithium concentrations and developmental, teratogenic, and behavioural responses in zebrafish embryos based on the OECD Test Guideline 236 - Fish Embryo Toxicity Test. Experiments were conducted in polystyrene and polypropylene plates under unmodified (pH 7.6) and acidified conditions (pH 6). Additionally, lithium speciation modelling was performed to evaluate potential changes in chemical speciation. No developmental and teratogenic changes were observed in exposed larvae. However, at higher target concentrations, measured lithium recoveries were higher in polypropylene plates, which was potentially attributed to higher inertness of polypropylene surfaces. Gene expression analysis further revealed material-dependent molecular responses, suggesting biological responses at the transcriptional level at low concentrations. Behavioural analyses showed reduced locomotor response at higher lithium concentrations, with stronger effects at pH 6. Speciation modelling demonstrated that lithium species distribution predominantly remained the same under all tested conditions, indicating that pH-related effects were unlikely driven by changes in lithium speciation. Protein-like compounds were formed under all experimental conditions, independent of plate material and pH, hinting towards in situ production and a limited role in binding large lithium fractions. Overall, our results show that experimental material and pH influence toxicity test outcomes and should therefore be carefully considered when designing aquatic toxicity tests.

Comprehensive quantification of per- and polyfluoroalkyl substances (PFAS) and extractable organofluorine (EOF) for assessing PFAS total in complex environmental matrices requires extraction methods capable of retaining chemically diverse fluorinated compounds. In this study, the performance of three solid-phase extraction (SPE) sorbents (weak anion exchange (WAX), weak cation exchange (WCX), and hydrophilic-lipophilic balance (HLB)) was comprehensively evaluated for the extraction of selected targeted PFAS and inorganic anions and determination of extractable fluorine from landfill leachate. Recovery experiments covering multiple PFAS classes, including PFCA, PFSA, zwitterionic PFAS, and bis-FASI, together with inorganic fluorinated anions, showed clear sorbent-dependent selectivity. WAX provided the most consistent recoveries across compound classes and yielded comparable concentrations of Σ33PFAS + BF4- and EOF, indicating retention of a broad fraction of fluorinated compounds and a closed fluorine mass balance. In contrast, WCX resulted in lower EOF concentration and a negative fluorine mass balance, attributed to matrix composition that emerged as a critical factor controlling EOF recovery, with divalent cations (Ca2+ and Mg2+) causing significant EOF suppression. HLB also yielded lower EOF concentrations, primarily due to poor retention of ultra-short-chain PFAS that contributed significantly to the overall fluorine balance, and similar behavior was observed for WCX. In addition, retention of inorganic fluorinated anions indicates that EOF concentrations included both organic and inorganic fluorinated compounds. The findings reveal that both sorbent chemistry and matrix chemistry critically influence EOF quantification, thereby affecting fluorine mass balance.

Schwertmannite and jarosite are naturally occurring iron (Fe) oxyhydroxysulfates with strong sorption capacities for hexavalent uranium [U(VI)] in various acidic sulfate-rich environments. These metastable minerals commonly undergo recrystallization, particularly in the presence of dissolved Fe2+ [Fe(II)aq], which may influence the fate of associated U(VI). Here, we quantified molecular-level changes in U repartitioning and speciation when U(VI)-sorbed schwertmannite and jarosite reacted with Fe(II)aq under near-neutral and anaerobic conditions over 2 weeks. The results show that Fe(II)aq additions promoted rapid mineral transformation to goethite via a dissolution-reprecipitation pathway, proceeding (near-completely) for schwertmannite but slowly and incompletely for jarosite. Importantly, even at early transformation stages when goethite likely only started forming on the surface of the transforming minerals, the recrystallization process led to near-complete retention of U, predominantly as U(VI), within the structure of the neo-formed goethite. Subsequent U reduction to U(V) increased with time but remained incomplete, even after extensive mineral transformation in the presence of 1-50 mM Fe(II)aq for 2 weeks. The results demonstrate that Fe(II)-promoted recrystallization of Fe-oxyhydroxysulfates can rapidly and persistently lock both U(VI) and U(V) into chemically stable goethite, with important implications for predicting U behavior and designing remediation strategies in various acidic and U-contaminated environments.

Crumb rubber, derived from recycled tyres, has been used as a sustainable, low-cost infill material. However, growing evidence suggests that tyre crumb rubber leachates can be highly toxic, underscoring the need for comprehensive risk assessments of different types of rubber and the development of safer alternatives. This study evaluated the acute toxicity of leachates from various infill materials, including black recycled tyre rubbers, coloured thermoplastic rubbers, and a mineral-based material ("Bioflex"), on key models of marine plankton. Specifically, we determined the effects of micronised crumb rubber leachates on the microalga Rhodomonas salina, embryos and nauplii of the copepod Acartia tonsa, and early developmental stages of the sea urchin Arbacia lixula. We also evaluated the toxicity of leachates extracted using an organic solvent compared to those obtained using filtered seawater, using R. salina as a model organism. Toxicity varied significantly among rubber types, with EC50 values ranging from 22.1mgL-1 to >1505mgL-1, depending on the organism, and biological endpoint. One of the tested tyre rubber crumbs consistently exhibited high toxicity across all test species, with EC50 values as low as 50mgL-1 for specific life stages. Among thermoplastic rubbers, green crumb rubber also showed high toxicity towards R. salina, with an EC50 of 25.7mgL-1. In contrast, the mineral-based material was only toxic to the early stages of A. lixula, exhibiting relatively low toxicity (EC50 = 2305mgL-1). In most cases, the toxicity of seawater-based leachates was comparable to that of solvent-based extracts, indicating that most toxic compounds affecting R. salina are water-soluble. Metal analysis revealed that the mineral-based material contained lower concentrations of toxic metals, such as zinc, and lower levels of polycyclic aromatic hydrocarbons than the other rubbers. This may partially explain its reduced toxicity to plankton. Our findings demonstrate that leachates from recycled crumb rubber and thermoplastic rubbers are toxic to marine plankton, although the effects are species-specific and dependent on the material composition. Our results also suggest that mineral-based infill materials (e.g., "Bioflex") are ecologically safer alternatives to rubbers. Overall, this study indicates that leachate pollution from recycled tyre rubber and thermoplastic rubber particles poses a potential risk to the pelagic food web, highlighting the importance of restricting or banning their use in areas near sensitive aquatic environments.

The effectiveness of biochar amendment for remediation purposes depends on many factors related to the biochar and the contaminated site. Therefore, each application must be evaluated site-specifically. To facilitate full-scale implementation, more information from field studies on biochar-amended contaminated sites, as well as cost-effective approaches to evaluate the remediation efficacy of specific biochar materials are needed. We studied the effects of biochar and peat on metal solubility and bioavailability in a contaminated soil in a fully factorial field trial. The biochar was produced from wood via gasification in a floating fixed-bed reactor at 750 degrees C. Soil solutions from field-installed lysimeters, grass (Lolium perenne L), and earthworms (Eisenia fetida) were analyzed. In addition, a standardized batch leaching test (ISO 21268-2:2019) was performed to evaluate its feasibility to mimic soil solution concentrations. The results showed that biochar generally reduced the solubility and uptake of cationic metals. In situ solubility of Cu and Hg was reduced more than 80%, and Zn up to 70%. Soil solution concentrations of Cr increased in biochar-amended soils, but this effect was reduced by peat. Peat had small effects on in situ solubility of other metals. For cations, the batch test showed the same trends as the soil solution, with biochar decreasing solubility. However, mobilization of colloids during shaking in the batch test induced artefacts, leading to an overestimation of the solubility of some metals, especially Pb and Hg, an effect that was enhanced by peat applications.

As the volume of plastic waste from electrical and electronic equipment (WEEE) continues to rise, a significant portion is disposed of in the environment, with only a small fraction being recycled. Both disposal and recycling pose unknown health risks that require immediate attention. Existing knowledge of WEEE plastic toxicity is limited and mostly relies on epidemiological data and association studies, with few insights into the underlying toxicity mechanisms. Therefore, this study aimed to perform comprehensive chemical screening and mechanistic toxicological assessment of WEEE plastic-associated chemicals. Chemical analysis, utilizing suspect screening based on high-resolution mass spectrometry, along with quantitative target chemical analysis, unveiled numerous hazardous compounds including polyaromatic compounds, organophosphate flame retardants, phthalates, benzotriazoles, etc. Toxicity endpoints included perturbation of morphological phenotypes using the Cell Painting approach, inflammatory response, oxidative stress, and endocrine disruption. Results demonstrated that WEEE plastic chemicals altered the phenotypes of the cytoskeleton, endoplasmic reticulum, and mitochondria in a dose-dependent manner. In addition, WEEE chemicals induced inflammatory responses in resting macrophages and altered inflammatory responses in lipopolysaccharide-primed macrophages. Furthermore, WEEE chemicals activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, indicating oxidative stress, and the aryl hydrocarbon receptor (AhR). Endocrine disruption was also observed through the activation of estrogenic receptor-α (ER-α) and the induction of anti-androgenic activity. The findings show that WEEE plastic-associated chemicals exert effects in multiple subcellular sites, via different receptors and mechanisms. Thus, an integrated approach employing both chemical and toxicological methods is essential for comprehensive assessment of the toxicity mechanisms and cumulative chemical burden of WEEE plastic-associated chemicals.

Potentially toxic elements (PTEs) have steadily become a serious environmental problem, especially regarding brownfields chosen for reuse, e.g., as a residential area. “Norra Hamnstaden” in Lidköping (Sweden) has a long history of industrial activity, including porcelain production with the resultant industrial waste deposited close by resulting in elevated levels of metals used for porcelain glazes, especially lead. To estimate the bioavailability of twelve PTEs (As, Ba, Pb, Cd, Co, Cu, Cr, Mn, Mo, Ni, V, Zn), their uptake by birches (Betula pendula) as well as Scots pines (Pinus sylvestris) was investigated through analyzing their leaves. Sampling was carried out on five trees once per month in the period from May to August. Different uptake patterns were observed for birches and pines, for the latter even varying with age. The birch samples showed higher contents of nickel, cobalt, molybdenum, and lead compared to the reference trees. Also, the pine needles had elevated lead levels, although by a lower factor. Birch leaves revealed surprising patterns of elevated element bioaccumulation factors, with barium reaching up to eight, offering the possibility to limit analyses to plant material for risk assessments instead of soil analysis.

The Stripa mine, located in Bergslagen, Sweden operated from the Middle Ages until 1977 and later served as a research facility for SKB until 1991, after which it was flooded. Recent studies show a notable increase in uranium concentrations in the mine water, reaching nearly 1 mg/L at 200 m depth, compared to historical levels of 10 mu g/L. This increase is linked to uranium(IV) oxidation by elevated dissolved oxygen. Further research should investigate key biogeochemical processes controlling uranium transport and long-term environmental persistence. The findings highlight regional environmental risks, including potential contamination of wells, emphasizing the mine's long-term environmental impact.

Climate change is driving extreme weather patterns, leading to prolonged droughts and more frequent intense precipitation events. These environmental changes will impact aquatic systems by altering essential water quality parameters such as temperature, redox potential, pH, suspended solids and organic matter, which influence pollutant solubility and determine ecosystem health as well as drinking water production. In this context, sediments play a crucial role as they represent both a sink and source of pollutants. Therefore, sediment toxicity testing is essential for accurate environmental risk assessments. However, there remains a gap regarding comprehensive sediment testing ap-proaches that integrate multiple biomarker responses.

The SEASON project uses an interdisciplinary approach combining strategies of environmental toxicology, analytical chemistry, andhydro geochemistry. The aim is to develop conceptual models for evaluating, understanding and predicting the impact of climate change effects on the fate, bioavailability, and toxicity of pollutants in the aquatic environment. This project focuses on risks associated with sediments contaminated by organic and inorganic pollutants, specifically metals and PFAS (per- and polyfluoroalkyl substances). By studying factors such as temperature, pH, microbial communities, and sediment-water interactions, the project seeks to understand how different climate change aspects affect pollutant behavior in aquatic ecosystems.

The project consists of four sub-projects. Three investigate different chemical groups and mixtures under varying water conditions, using zebrafish (Danio rerio) as the main model organism. These studies will include in vitro and in vivo assays, microcosm experiments, microbiome studies and chemical analyses. The fourth subproject will integrate the results to develop a predictive model for sediment risk assessment.

Sediment contact assays will be performed to evaluate the effects of contaminated samples on zebrafish embryos by measuring teratogenicity, developmental toxicity, behavioral changes, and gene expression. In microcosm studies, we will vary pH and mimic increased precipitation events to assess pollutant toxicity in adult zebrafish including sex-related toxicity differences, reproduction, and behavior. Effect-directed analysis (EDA) will be used to identify key toxicants in the samples. Microbiome analysis using metagenomic sequencing will focus on how contaminated sediments alter bacterial communities, which in turn can affect pollutant distribution and bioavailability. Chemical analyses will quantify PFAS, metals, and their speciation throughout the study. Ultimately, the project will integrate these data to develop models that increase our understanding of the impact of climate change on sediment contamination and aquatic ecosystem health.

Chemical and microlitter (ML) pollution in three Estonian coastal areas (Baltic Sea) was investigated using mussels (Mytilus trossulus). Polycyclic aromatic hydrocarbons (PAH) in mussel tissues were observed in moderate levels with high bioaccumulation factors for the more hydrophilic and low molecular weight PAH (LMW PAH), namely anthracene and fluorene. Tissue concentrations of polybrominated diphenyl ethers (PBDE) and cadmium within mussel populations exceeded the Good Environmental Status thresholds by more than 200% and 60%, respectively. Multiple contamination at the Muuga Harbour site by tributyltin, high molecular weight PAH, including the highly toxic benzo[c]fluorene and PBDE, coincided with the inhibition of acetylcholinesterase activity and a lower condition index of the mussels. The metabolization and removal of bioaccumulated LMW PAH, reflected in the dominance of oxy-PAH such as anthracene-9,10-dione, is likely associated with the increased activity of glutathione S-transferase in caged mussels. Only a few microplastic particles were observed among the ML in mussel tissues, with coloured cellulose-based microfibers being the most prevalent. The average concentration of ML in mussels was significantly higher at the harbour area than at other sites. The integrated biomarker response index values allowed for the differentiation of pollution levels across studied locations representing high, intermediate, and low pollution levels within the studied area.